Transcript Bio 257 Unit 1 day 6

Bio 257 Unit 1 day 6
Topics:
 Ch 5
Chapter 5 Topics
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Skin Generalized Structure & Function
Epidermis structure/ function
Dermis Structure/ function
Hypodermis Structure/ function
Skin Color
Accessory organs
Skin as Diagnostic Tool
Homeostasis & Skin
Aging & Skin
Cutaneous Membranes
 Commonly referred to as the skin
 Releases sweat, oil (sebum), for
lubrication, protection & excretion
Integumentary System
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Structure:
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consists of 2 major layers
1. Epidermis
2. Dermis
5 Functions:
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Protection
Sensation
Vitamin D production
Temperature regulation
Excretion
Epidermis
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Structure:
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Keratinized Stratified Squamous Epithelium
Cells in the Epidermis
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5 layers (Can Little Girls Speak German)
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Epidermis
Structure:
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5 layers (Can Little Girls Speak German)
1. Stratum corneum
2. Stratum lucidum
3. Stratum granulosum
4. Stratum spinosum
5. Stratum germinativum
Epidermis
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Structure:
 Keratinization =
Keratin =
Epidermis
 Structure:
 Melanin =
- Increased production of melanin
occurs during:
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3.
Dermis
 Made up of dense (irregular) connective
tissue that contains fibroblast, fat cells
and macrophages
 Has fewer fat cells and blood vessels
than hypodermis
 Contains nerve endings, hair follicles,
smooth muscle, glands, and lymphatic
vessels
Hypodermis
 Attaches skin to underlying bone
and muscle and supplies it with
blood vessels.
 Not part of skin Subcutaneous
tissue.
 Made up of loose connective tissue
and fat.
Accessory Skin Structures
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Hair
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Muscles-arrector piligoose flesh
Glands
1. Sebaceous glands->sebum
2. Sweat glands
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Nails
Merocrine
Apocrine
Skin as a diagnostic tool
 Observed easily and often reflects
events occurring in other parts of
the body.
– Cyanosis-bluish color indicative of
impaired circulatory or respiratory fxn
– Jaundice-yellowish skin color resulting
from accumulation of bile pigments in
blood and tissue indicative of
impaired liver fxn
Effects of aging on the skin
 Epidermis thins and collagen in dermis decreases.
 Probability of skin infections increase and skin heals more slowly.
 Decreased elastic fibers in the dermis and loss of fat from the
hypodermis cause sagging and wrinkling.
 Poor ability to regulate body temp due to decreased activity in
sweat glands and diminished blood supply in the dermis.
 Sebaceous gland activity decreases leading to drier skin.
 Melanocytes increase in some areas  age spots.
 Gray hair results from diminished melanin production.